The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Generally, vehicles are subjected to a water-proofing test in a shower booth provided in a manufacturing line or other place. In the shower booth, high-pressure water is sprayed to a vehicle, and a water-proofing test is carried out on the vehicle to which the high-pressure water has been sprayed.
Conventionally, the water-proofing test is performed such that a worker determines whether water has penetrated into a vehicle by directly observing the vehicle with his or her naked eye. Generally, however, water penetrating into a vehicle mainly stays in a portion which is hard to observe from the outside, such as a gap between a vehicle body frame and various protective layers provided to cover the vehicle body frame. Therefore, with the conventional method for a water-proofing test, it is difficult to accurately test water-proofing performance of a vehicle.